Loop drier girt



May 5, 1953 A. o. HURXTHAL 2,637,093

LOOP DRIER GIRT Filed May 12, 1952 2 SHEETS- SHEET 1 May 5, 1953 A. o. HuRxTHAL LOOP DRIER GIRT 2 SHEETS-SHEET2 Filed May 12, 1952 Patented May 5, 1953 UNITED STATES PATENT OFFICE LOOP DRIER GIRT Alplieus O. Hurxthal, Philadelphia, Pa., assignor to Proctor and Schwartz, Inc., a corporation of Pennsylvania 8 Claims.

4The present invention relates to new and useful improvements in loop dryer girts for use in loop br festcen dryers, and more particularly to new `and useful improvements in expanding sleeves for loop dryer girts which will expand uniformly throughout their length and also will prevent the web conveyed through the dryer from being 'marked or otherwise disigured.

Prior to the present invention expansion sleeves for loop dryer girts have usually consisted of a woven metallic cover for the girt which could be lengthened or expanded as the girt passes through the drying chamber in order to remove wrinkles r folds from the material carried by the girt. Expansion sleeves manufactured of metallic material have a number of inherent disadvantages. The major disadvantage is that the material carried by the sleeve becomes marked or disiigured. This is due to the fact that metallic expansion sleeves have a high heat transfer coeficient and are easily overheated during passage through the drying chamber. The ideal covering for loop dryer girts is a braided asbestos material. Howeveigvbraided asbestos, by itself, will not expand uniformly throughout its length and thus asbestos has not heretofore been used in conjunction with expanding sleeves for loop dryer girts. It has been found that the braided asbestos will expand a considerable amount in the area adjacent the place where the asbestos-is secured to the girt and will not expand over the remaining length of the girt. The present invention overcomes this and combines the advantages obtained by using an asbestos cover for loop dryer girts along with the desirability of the uniform expansion obtained by using a metallic expanding sleeve. This v'is accomplished in the present invention by braid- .ing an asbestos cover directly over a rlat steel coil spring on the expanding girt. By this construction, the spring carries the asbestos sleeve and ycauses uniformity of expansion and the asbestos `sleeve supports the material being dried and prevents it from becoming marked.

With the foregoing in mind the principal object of the present invention is to provide a novel expanding girt for loop or festoon dryers which has a low heat transfer coeflicient and will not mark or disgure the material being conveyed through the dryer.

Another object of the present invention is to provide a novel expanding girt having a braided asbestos cover which may be uniformly expanded throughout the length of the girt.

rAstill further object of the present invention is to provide a novel expanding girt for loop or festoon dryers having the features and Characteristics set forth which is of relatively simplied construction and entirely efficient and effective in operation and use.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth and described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of a loop or festoon dryer incorporating the expanding girts of the present invention.

Fig. 2 is a plan view of the expanding girts taken on line 2 2, Fig. 1;

Fig. 3 is an enlarged transverse sectional View through the dryer taken on line 3 3, Fig. 2, and illustrates the construction and the method of supporting the expanding girts Fig. l is an enlarged longitudinal sectional View of one end of the expanding girt illustrated in Fig. 3;

Fig. 5. is a transverse sectional View taken on line 5 5, Fig. 4, illustrating the method for irnparting intermittent rotary movement to the expanding girts;

Fig. 6 is an enlarged transverse sectional view taken on line 6 6, Fig. 5; and,

Fig. 7 is a fragmentary perspective View of one end. of the metallic expanding member.

With reference to the drawings, Fig. 1 illustrates a conventional loop or festoon dryer wherein a web w is supported and conveyed through a dryer chamber l by means of a conveyor 2. This conveyor 2 comprises a pair of side chains 3, 3 which are arranged to travel continuously upon supporting rails 4, l mounted Within the chamber l. Extending between and supported at their opposite ends by the chains 3, 3 is a series of expandible girts 5 which are mounted on the chains 3, 3 for relative rotary movement. 4The web w is formed into loop or festoons J3 successively by passing over a rotating drum 6 which feeds the web downwardly between adjacent pairs of girts 5 while the upper run of the conveyor moves beneath the drum 6 at a relatively slower speed than the peripheral speed of the drum.

The present invention relates to the construction of the web supporting girts 5 and particularly to the expansible feature of the girts which permits the girts to expand uniformly throughout their length and also prevents marking or disguration of the material carried by the girts. In accordance with the present invention, each expandible girt 5 consists of a central tubular member 1 which extends entirely across the dryer chamber. The tubular member 'l is formed from sheet material and has a lock seam 8 disposed interiorly thereof, as shown in Figs. 4 and 5. Positioned at each end of the tubular member 'i is a plug 9 which closes the open end of the tube and provides a means to support the tube i. The tube 'l is depressed into recesses li in the plugs 8, as shown. in Fig. 4, to secure lthe tube to the plug. In addition, a longitudinal slot i2 aiong one side of the plug 8 is provided to receive the inwardly extending lock seam 3 and prevent rel ative rotary movement between the plug S and the tube I.

Extending outwardly from each plug S along the longitudinal axis thereof is apin or trunnion I3 which secures the girt to the chains 3, 3. The pins I3 project through openings centrally of each link of the chains 3, 3 for example', as illustrated in Figs. 2 and 4. Rollers iii carried at the ends of each link of the chains support the chains on the rails e, d. Postioned between the girt 5 and the chains 3, 3 and carried by the pins i3 are spacers l5 which prevent relative transverse movement of the girtsin the dryer.

VIf desired, intermittent rotary movement may be imparted to the girts 5 to prevent any cne portion of the web w from contacting the surface of the girt throughout the entire path of travel of the web through the dryer therebyl permitting the web to be dried uniformly. To accomplish this, a star-wheel i6 is secured to the left-hand end of each girt. The star-wheels ifi areormed, for example, as illustrated in Fig. 5 and have a plurality of inwardly extending radial slots il therein. The peripheral surface of the star-wheel between adjacent slots il isn'at in order to engage a projecting ledge i3 which extends outwardly beneath the side rail i and prevent rotation of the girt. Positioned at predetermined spaced intervals alongside rails li and projecting outwardly therefrom is a plurality of pins 2i which are adapted to be engaged in the slots il and cause the star-wheel It to be rotated a fraction of a turn. The projecting ledge i3 is cut away or slotted, for example, as illustrated at 22 in Figs. 2 and 5 immediately beneath each of the pins i3 to permit rotation of the star-wheel I3 when it engages the pins 2l. By this construction, the girts are .intermittently rotated at predetermined positions throughout the length of the dryer chamber.

In accordance with the present invention, sleeves 23, 23 are positioned Yabout the tubular member l at each end thereof for longitudinal movement with respect to the member i.V Relative longitudinal movement of the sleeve 23 is limited by means of slots 24 at each side of the tubular member 7 which are adapted to receive a pin 25 secured to the sleeves 23, as shown in Fig. 6. A at steel coil spring 26 is positioned around each of the girts 5 and secured at its opposite ends, for example, by means of spot welding, to each sleeve 23. The coil spring 23 ,will expand uniformly along its length when the sleeves 23, 23 Vare moved outwardly away from each other and thus, any expandible material carried by the coil spring 23 will expand or contract in the same manner as the spring. rEhe spring 23 also serves the purpose of normally urging the sleeves 23, 23 toward their inner limit positions.

During manufacture oiA the girt 5 an expandible cover 2l is positioned about the spring 26 and secured at its opposite ends to the sleeves 23 by means of clamps `28, 23. The cover 2l preferably is braided directly on the spring 26 and may be formed of any heat resistant material. Asbestos is an ideal covering for a girt since it has a low heat transfer coefficient and will not become overheated and mark or disgure the Inaterial being conveyed through the dryer. In addition, if an asbestos cover is braided about the at spiralspring 26 it `will expand and contract uniformly along its length when the sleeves 23 are moved relative to the tubular member l.

Girts of thistype are usually expanded as they pass through the dryer to remove wrinkles and folds from the material carried by the girts. In the present inventionexpansion of the spring 26 and-braided asbestos cover 2l' is accomplished by means of collars'3l, 3| secured to the outer end Vof eachsleeve 23 and adapted to engage guide rails 32, 32 which extend longitudinally of the dryer. The guide rails 32, 32 diverge outwardly from each other as shown in Fig. 2 and thus, as the expanding girts pass through the drying chamber the braided lcover 2| is expanded uniformly. The guide rails 32 engage the collars 3l during both the upper andlower runs ofthe conveyor and during the` lower run of the conveyor the guides converge inwardly and'permit thegirts to be contracted.

From the foregoing it will be observed that-the present invention provides ya novel expanding girt for loop or festoon dryers which has a low heat transfer coefficient and will not mark or disgure the material passing through the dryer. In addition, the present invention provides a novel expanding girt having a braided asbestos cover which may be uniformly expanded throughout the length of the girt.

While a particular embodiment of the present invention has been illustrated and described herein it is not intended to limit the invention to such a disclosure and changes and modiiications may be incorporated and embodied therein within the scope ofthe following claims.

Iclaim:

l. In an expansible girt for loop or festoon dryers comprising a central girt supporting member, sleeves slidably mounted exteriorly on said girt supporting member adjacent opposite ends thereof for coaxial movement between predetermined inner and outer limit positions, an expansible-contractible member circumscribing said central girt supporting member and having its opposite ends anchored respectively on said sleeves, and a braided tubularheat resistant cover closely surrounding said expansible-contractible member and adapted to expand and -contract in conjunction with said expansible-contractible member.

2. In an expansible girt for loop or festoon dryers comprising a central girt supporting member, sleeves slidably mounted exterior-ly on said girt supporting member adjacent opposite ends thereof for movement coaxially between predetermined inner and outer limit positions, arflat spiral spring surrounding said girt supporting member and securedat its opposite ends to said sleeves and operable normally to urge said sleeves toward their inner limit positions, and a braided tubular heat resistant cover closely surrounding Said spring and expansible and contractible in conjunction therewith.

3. In an expansible girt for loop or estoon dryers comprising a centralgirt supporting member and a pair of outwardly diverging guides extending longitudinally of the drying chamber, sleeves slidably mounted exteriorly. on said girt supporting member adjacent opposite ends thereof for coaxial movement between predetermined inner and cuter limit positions, means interconnecting said sleeves with said guides and actuatable to move said sleeves toward one limit position, an expansible-contractible member circumscribing said central girt supporting member and having its opposite ends anchored respectively on said sleeves, said expansible-contractible member operating normally to urge said Sleeves to the other limit position, and a braided tubular heat resistant cover closely surrounding said expansible-ccntractible member and adapted to expand and contract in conjunction with said eXpansible-contractible member.

4. In an expansible girt for loop or festoon dryers comprising a central girt supporting member and a pair of outwardly diverging guides extending longitudinally ei the drying chamber, sleeves slidably mounted exteriorly on said girt supporting member adjacent opposite ends thereof for movement coaxially between predetermined inner and outer limit positions, means interconnecting said sleeves with said guides and actuatable to move said sleeves toward their outer limit positions, a at spring surrounding said girt supporting member and secured at its opposite ends to said sleeves operable normally to urge said sleeves toward their inner limit positions, and a braided tubular heat resistant cover` closely surrounding said spring and expansible and contractible in conjunction therewith.

5. In an expansible girt for Loop or festoon dryers comprising a central girt supporting member and a pair of outwardly diver-ging guides extending longitudinally of the drying chamber, sleeves slidably mounted exteriorly on said girt supporting member adjacent opposite ends thereof for coaxial movement between predetermined inner and outer limit positions, a collar carried by each of said sleeves for engagement with said guides and actuatable thereby to move said sleeves toward one limit position, an expansiblecontractible member circumscribing said central girt supporting member and having its opposite ends anchored respectively on said sleeves, said eXpansible-contractible member operating normally to urge said sleeves to the other limit position, and a braided tubular heat resistant cover closely surrounding said eXpansible-contractible member and adapted to expand and contract in conjunction with said eXpansible-contractible member.

6. In an expansible girt for loop or festoon dryers comprising a central girt supporting member carried by conveyor chains at opposite sides of the drying chamber and a pair of outwardly diverging guides extending longitudinally of the drying chamber, sleeves slidably mounted exteriorly on said girt supporting member adjacent opposite ends thereof for coaxial movement between predetermined inner and outer limit positions, a collar carried by each of said sleeves for engagement with said guides and actuatable thereby to move said sleeves toward their outer limit positions, an eXpansible-contractible member spirally circumscribing said central girt supporting member under tension and having its opposite ends anchored respectively on said sleeves, said eXpansible-contractible member operating normally to urge said sleeves to their inner limit positions, and a braided tubular asbestos cover closely surrounding said expansiblecontractible member and adapted to expand and contract in conjunction with said expansiblecontractible member.

7. In an expansible girt for loop or festoon dryers comprising a central girt supporting member and a pair or outwardly diverging guides extending longitudinally of the-drying chamber, sleeves slidably mounted exteriorly on said girt supporting member adjacent opposite ends thereof for movement coaxially between predetermined inner and outer limit positions, a collar carried by each of said sleeves for engagement with said guides and actuatable thereby to move said sleeves toward one limit position, a dat spring surrounding said girt supporting member and secured at its opposite ends to said sleeves operable normally to urge said sleeves toward their other limit position, and a braided tubular heat resistant cover closely surrounding said spring and expansible and contractible in conjunction therewith.

8. In an expansible girt for loop or festoon dryers comprising a central girt supporting member carried by conveyor chains at opposite sides of the drying chamber and a pair of outwardly diverging guides extending longitudinally of the drying chamber, sleeves slidably mounted eXteriorly on said girt supporting member adjacent opposite ends thereof for movement coaxially between predetermined inner and outer limit posiions, a collar carried by each of said sleeves for engagement with said guides and actuatable thereby to move said sleeves toward their outer limit positions, a dat spiral spring surrounding said girt supporting member and secured at its opposite ends to said sleeves under tension and operable normally to urge said sleeves toward their inner limit positions, a braided tubular asbestos cover closely surrounding said spring and expansible and contractible in conjunction therewith, and means for intermittently rotating the expansible girt during passage through the drying chamber.

ALPHEUS O. HURXTHAL.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,603,065 Case Oct. 12, 1926 1,613,460 Hurxthal Jan. 4, 1927 2,436,719 Hurxthal Feb. 24, 1948 2,468,892 OKeeffe May 3, 1949 

